Multi-threaded cookie management

gistfile1.cs

private readonly Dictionary<string, Cookie> globalCookies = new Dictionary<string, Cookie>();

public void DoRequest(Uri uri)
{
    var localCookies = new CookieContainer();
    lock(globalCookies)
    {
        foreach(var cookie in globalCookies)
        {
            localCookies.Add(cookie.Value);
        }
    }
    var origCookies = new HashSet<string>(localCookies.GetCookies(uri).Cast<Cookie>().Select(c => c.Name));
    ReallyDoWebRequest(uri, localCookies);
    lock(globalCookies)
    {
        var currCookies = new HashSet<string>(localCookies.GetCookies(uri).Cast<Cookie>().Select(c => c.Name));
        foreach(var origCookie in origCookies)
        {
            if (!currCookies.Contains(origCookie))
            {
                // smazaná cookie
                globalCookies.Remove(origCookie);
            }
        }
        foreach(var cookie in localCookies.GetCookies(uri).Cast<Cookie>())
        {
            // nová?
            if (!origCookies.Contains(cookie.Name))
            {
                globalCookies.Add(cookie.Name, cookie);
            }
            // změněná?
            else
            {
                globalCookies[cookie.Name] = cookie;
            }
        }
    }
}

private void ReallyDoWebRequest(Uri uri, CookieContainer cookies)
{
    // ...
}